Lifting device and method of use thereof

ABSTRACT

A lifting device and method of use permit objects having a flat bottom supported on particulate material to be readily lifted. The device includes an elongate shaft member extending in a longitudinal direction between respective first and second ends. A hook member is supported on the first end of the shaft member to extend substantially straight along a hook axis lying substantially perpendicular to the longitudinal direction of the shaft member. A gripping member supported on the shaft member adjacent the second end permits gripping in a hand of a person. The substantially perpendicular configuration of the hook member readily permits rectangular objects to be well supported on the hook member for lifting heavy objects including pre-cast concrete sidewalk slabs and the like.

[0001] This application claims priority under 35 U.S.C. 119 from U.S.Provisional Application Serial No. 60/466,780 filed May 1, 2003.

FIELD OF THE INVENTION

[0002] The present invention relates to a lifting device for liftingobjects, and more particularly the invention relates to a kit of partsincluding plural lifting devices and a method of use thereof forextracting, lifting, re-positioning, or accurately repositioning variousobjects, for example pre-cast concrete members including sidewalk slabsand blocks, landscape ties, or other large/heavy items typically havinga flat bottom supported on particulate material.

BACKGROUND

[0003] Various configurations of lifting devices are known in the priorart which include a handle and a hook member supported thereon forgripping an object. Known configurations of hook members are typicallycurved in profile or lie at an awkward angle in relation to a shaft ofthe lifting device such that it would be awkward or impossible to liftlarge heavy objects such as pre-cast concrete panels and blocks.Furthermore, known prior art designs of lifting devices generally do notpermit the hook member thereof to be received within the narrow gaptypically located between adjacent slabs in a sidewalk formed ofpre-cast concrete slabs lying adjacent one another.

SUMMARY

[0004] According to a first aspect of the present invention there isprovided a lifting device comprising:

[0005] an elongate shaft member extending in a longitudinal directionbetween respective first and second ends;

[0006] a hook member supported on the first end of the shaft member, thehook member being substantially straight along a hook axis lyingsubstantially perpendicular to the longitudinal direction of the shaftmember; and

[0007] a gripping member supported on the shaft member adjacent thesecond end thereof for being gripped in a hand of a person.

[0008] The substantially perpendicular configuration of the hook memberreadily permits rectangular objects to be well supported on the hookmember for lifting heavy objects including pre-cast concrete sidewalkslabs and the like.

[0009] According to a second aspect of the present invention there isprovided a lifting kit for lifting objects having a flat bottomsupported on particulate material, for example pre-cast concrete membersand the like in which the kit comprises a plurality of lifting devicesin accordance with the first aspect of the present invention.

[0010] According to a further aspect of the present invention there isprovided a method of lifting an object having a flat bottom supported onparticulate material on the ground, the method comprising:

[0011] providing at least one lifting device comprising an elongateshaft member; a hook member supported on a first end of the shaft memberto extend substantially straight along a hook axis lying substantiallyperpendicular to a longitudinal direction of the shaft member; and agripping member supported on the shaft member adjacent a second endthereof;

[0012] positioning the hook member of said at least one lifting deviceadjacent and parallel to a respective side edge of the object;

[0013] lowering the hook member of said at least one lifting devicealong the respective side edge below a respective bottom edge of theobject;

[0014] rotating the hook member of said at least one lifting deviceabout a longitudinal axis of the shaft member until the hook member ispositioned below the object; and

[0015] lifting said at least one lifting device.

[0016] The shaft member and the hook member may be integrally formed ofa single rod of material which has been deformed and which is circularin cross section at the first end thereof.

[0017] The shaft member may be approximately two feet in length or anyother suitable length, possibly in the range of 1.5 to 3 feet, to permitperson to lift an object off the ground while in a comfortable standingposition.

[0018] The shaft member and the hook member preferably have a similarcross sectional dimension which is substantially less than ½ inch.

[0019] The gripping member may comprise a handle mounted on the shaftmember transversely to the longitudinal direction of the shaft memberand the hook axis which is either injection molded in place onto theshaft or later secured to the shaft by welding or other suitablefastening means. In either instance, the handle preferably remains fixedin orientation relative to the shaft member and the hook member oncemounted thereon.

[0020] The method may include providing a plurality of lifting devicesand positioning the lifting devices along opposing side edges of theobject.

[0021] When lifting an object comprising a first pre-cast concretesidewalk slab, positioned adjacent a second sidewalk slab of similarconfiguration, the method preferably includes inserting the hook memberof said at least one lifting device in a gap defined between the firstand second sidewalk slabs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the accompanying drawings, which illustrate exemplaryembodiments of the present invention:

[0023]FIG. 1 is a perspective view of the lifting device.

[0024]FIG. 2 is a side elevational view of a pair of lifting devicesbeing used to lift a pre-cast concrete slab in which only one of thelifting devices is engaged below the slab.

[0025]FIG. 3 is a side elevational view similar to that of FIG. 2 inwhich both lifting devices are engaged below the concrete slab.

[0026]FIG. 4 is a top plan view in accordance with FIGS. 2 and 3.

[0027]FIG. 5 is a top plan view of a first embodiment of the handle ofthe lifting device.

[0028]FIG. 6 is a side elevational view of the handle of FIG. 5.

[0029]FIG. 7 is a side elevational view of the shaft and hook member ofthe lifting device for use with the handle of FIG. 5.

[0030]FIG. 8 is a front elevational view of the lifting device inaccordance with FIG. 5 in an assembled position.

[0031]FIGS. 9A through 9C are perspective views of a plurality oflifting devices being inserted adjacent opposing side edges of aconcrete slab to be lifted.

[0032]FIGS. 10A through 10C are perspective views of the lifting devicesin accordance with FIGS. 9A through 9C as they are rotated to positionthe hook members below the concrete slab.

[0033]FIGS. 11A through 11C illustrate the various steps in lifting theconcrete slab once the hook members are engaged below the slab.

[0034]FIG. 12 is a perspective view of a second embodiment of thehandle.

DETAILED DESCRIPTION

[0035] Referring to the accompanying drawings, there is illustrated alifting device generally indicated by reference numeral 10. The device10 is normally available as a kit of two or four lifting devices ofsimilar configuration which are used by persons P for lifting pre-castconcrete members, for example sidewalk slabs S or blocks and any otherlarge heavy object generally having a flat bottom surface B supported onparticulate material on the ground G, for example crushed stone or thelike.

[0036] While various embodiments of the device 10 are shown in thedrawings, the common features will first be described herein. The device10 generally includes an elongate shaft 12 which extends in alongitudinal direction between a first end 14 and a second end 16. Ahook member 18 is mounted on the first end 14 of the shaft to liesubstantially perpendicularly at a slight acute angle of approximately87 degrees to the longitudinal direction of the shaft. The hook memberextends straight along a respective hook axis which lies in thedirection of the hook member generally perpendicularly to thelongitudinal direction of the shaft. The hook member and the shaft areintegrally formed of a single cold rolled steel rod which is {fraction(3/16)} of an inch in diameter by bending the first end 14 of the shaft.The hook member 18 is approximately one inch in length while the shaft12 is nearly two feet in length. By bending the angle to a few degreesless than 90 degrees between the hook member and the shaft, slightbending of the shaft toward an object to be lifted when weight isapplied thereto is offset.

[0037] The second end 16 of the shaft mounts a handle 20 thereon. Thehandle 20 lies in common plane with the shaft member yet a longitudinaldirection of the handle 20 is oriented perpendicularly to the hook axis.The handle 20 once attached to the shaft 12, is fixed in orientationrelative to the shaft to control direction of the hook member 18 byrotating the handle 20 and the shaft fixed thereto.

[0038] In a first embodiment as shown in FIGS. 5 through 8, the handlegenerally comprises a cold rolled steel rod of half an inch in diameterand approximately five inches in length. A mounting hole 21 extendsthrough the handle 20 at a central location perpendicular to alongitudinal direction of the handle. The mounting hole receives thesecond end of the shaft therein for mounting the handle 20perpendicularly to the shaft 12 by a suitable welding operation. Theends of the handle are rounded and tapered to remove the sharp edgestherefrom.

[0039] In a further embodiment of the handle 20 illustrated in FIG. 12,the second end 16 of the shaft member is deformed by bending and thehandle 20 is injection molded of suitable high strength plastic materialabout the deformed second end 16 of the shaft member. The deformation ofthe shaft member at the second end assists in retaining the handle aboutthe shaft member. Any type of deformation including bending, marring,texturing, or otherwise modifying the smooth cross-sectional shape ofthe shaft at the second end would be suitable to assist in retaining theinjection moulded handle about the second end of the shaft.

[0040] In either embodiment, lifting a pre-cast concrete sidewalk slab Sis typically accomplished with two persons P, each provided with a pairof lifting devices 10 held by their respective handles 20 in therespective hands of the person. As illustrated in FIGS. 9A through 9Ceach person inserts their respective pair of lifting devices within agap between the slab and an adjacent slab along a respective side edgeof the slab to be lifted. The lifting devices 10 are each preferablelocated adjacent a respective one of the four corners of the slab formaximum stability. The hook members are oriented parallel and adjacentto the edge of the slab to be lifted so that the hooks may be loweredwithin the gap until positioned below a bottom edge of the slab. Once inthis position the hook members may be rotated as illustrated in FIGS.10A through 10C by rotating the shafts about their respectivelongitudinal axis as the person twists the respective handles 20 usingtheir hands. Once the hook members are perpendicular to the side edgesof the slab and located directly adjacent the bottom side of the slab,the slab is prepared to be lifted as illustrated in FIGS. 11A through11C. The various stages are summarized in FIGS. 2 and 3 in which thethree steps of insertion, rotation and lifting are also shown.

[0041] A set of up to four lifting devices are typically provided foruse in various modes and combinations to manipulate large heavy itemsthat have a distinct flat bottom surface, particularly items in theoutdoor/landscaping area like pre-cast concrete slabs, railway ties, andlandscape ties. Each lifting device consists of a thin round rod shaftwhich is approximately 2 feet in length with a small 87 degree flat hookhaving an acute interior angle and which is approximately 1 inch inlength. The hook is bent at one end and a handle which is approximately5 inches in length is attached to the shaft in the center of the handleat the other end so as to lie perpendicularly to the hook. An operatorof the lifting device would grasp a lifting device by its handle in onehand.

[0042] To extract and lift a block/tie, two operators would each use twolifting device, one in each operator's hand. Each operator would lowerthe hook of each lifting device below the bottom surface of the slab/tiewith the hook positioned parallel to the edge of the block/tie surface,twist each lifting device 90 degrees in the direction to position eachhook under the block/tie bottom surface, then both operators would liftthe block/tie with the lifting device in the “set” position.

[0043] To release the block/tie in the exact position and locationdesired, the operators would reverse the process used to lift ablock/tie. The operators would position the block/tie over the positionand location desired. The operators would lower the block/tie into theposition by lowering the lifting device in their hands. Once theblock/tie rests in its final position, each operator twists each oftheir lifting device 90 degrees to “unset” the hooks by positioning thehooks parallel to the edge of the block/tie surface. The operators thenremove each of their lifting devices from the work area by lifting eachlifting device.

[0044] The lifting devices can be used in various other mannersincluding: 1) using one operator with one or two lifting devices to liftone end of the block/tie for fine adjustments to the elevation of theblock/tie with levelling material, for example sand and the like; 2)using the hook to scrape or clear the material between two blocks thatwas originally used to set the blocks; or 3) using the lifting device asan extension of the operator's hand to reach for items.

[0045] A single lifting device apparatus is generally comprised of ashaft, a hook and a handle.

[0046] The shaft comprises thin round rod approximately {fraction(3/16)} inch in diameter with an approximate length of two feet andconsisting of a high strength material to provide the required tensionstrength, torsion strength, and bending resistance to operate thelifting device's lowering, twisting, and lifting of the anticipatedweights to be manipulated.

[0047] The hook comprises a small length flat hook approximately oneinch in length which is bent into one end of the shaft at 90 degrees ofthe main shaft or an acute interior angle in the order of 87 degrees.The end of the shaft where the hook is created is generally referred toas the bottom end of the shaft.

[0048] The handle comprises a length of material to adequately supportany operator's entire hand when the operator grasps the handle, forexample approximately five inches, and a thickness and shape to providethe operator's hand comfort when twisting the lifting device and liftingpotentially heavy weight.

[0049] The handle is solidly attached on the opposite end of the shaftto the bottom end where the hook was created. The end where the handleis attached on the shaft is referred to as the top end of the shaft. Thehandle is attached at its mid-length point to the top end of the shaft.The handle is attached at 90 degrees of the main shaft and perpendicularto the position of the hook.

[0050] The lifting device would typically be held by the handle in anoperator's left and/or right hand with the operator's hand positioned onthe handle so that the shaft of the lifting device is centered at thecenter of the operator's hand.

[0051] An operator using the lifting device in one or both hands wouldposition the hook of each lifting device below the bottom flat surfaceof the block/tie to be manipulated and perpendicular to the edge of thesurface of the block/tie where the lifting device is positioned besidethe block/tie. This operation is referred to as setting the hook. Anoperator using the lifting device would then lift directly upward andevenly by all used lifting devices on the handles thereof, therebylifting the block/tie off the ground surface where it rested. Thisoperation is referred to as lifting.

[0052] The operators that have completed the operation of lifting canreturn the raised block/tie back to rest upon the ground surface byhaving the operators of all lifting devices lower all lifting devicesused in the original lifting operation to the point where the block/tieis resting upon the ground surface. This operation is referred to aslowering.

[0053] The operators that have completed the operation of lowering wouldremove the lifting devices used to perform the lowering operation bytwisting the handle of each used handle by 90 degrees. The operatorswould then lift all the used lifting devices in the operation in astraight up manner, thereby removing the lifting device from the workarea. This operation is referred to as unsetting the hook.

[0054] The operator could use the lifting device as an apparatus toclear any debris or loose material between closely positioned blocks.This loose material between block is commonly levelling/packing sandwhich needs to be removed in the location whereby the lifting deviceneeds to be lowered during the operation of setting the hook so that thelifting device's hook could be positioned below the bottom surface ofthe block.

[0055] The operator could use the lifting device as an apparatus toextend the reach of the operator's arm/hand to reach for an item thatwould normally be out of the operator's reach.

[0056] Unique functional components or features of the lifting devicemay include a very narrow shaft and hook to allow for insertion of theshaft/hook between very narrow spaces between concrete slabs while alsoproviding the critical tension strength to support the heavy weight ofthe slab, the critical torsion strength to allow the hook to rotate indirect proportion to the amount of rotation that the handle rotates(especially when the shaft is at a length required for a person to standas he/she uses the apparatus), and bend resistance to allow the 90degree angle to be maintained when the significant weight of the slab isplaced onto the hook as the slab is lifted by the apparatus.

[0057] The device is provided with a shaft length that is long enoughfor a short adult to stand upright (with bent knees) when using theapparatus and still provide all the attributes of the last statement.

[0058] The shaft is in a round rod shape to allow for the shaft/hook tobe rotated 90 degrees easily without it binding between the narrow crackbetween the slabs.

[0059] The hook at the bottom of the shaft bends a sharp 90 degrees fromthe shaft to allow the edge of the slab to rest right up into the 90degree angle where the most strength of the material exists to hold thesignificant weight of the slab.

[0060] The hook is relatively small in length (approximately 1″) toallow the compromise of the hook being able to easily rotate 90 degreesas it pushes ground material out of its way under the slab while stillproviding enough support to the slab for the apparatus during the lift.

[0061] The hook is flat surfaced from the point of the 90 degree angleto the tip of the hook so that the entire surface of the hook contactsthe bottom surface of the slab, providing more support and less stressto one point on the hook.

[0062] The handle provides comfort in the operator's hand when he/sheapplies the rotation and lifts the heavy weight applied to the hook asthe operator lifts with the handle.

[0063] The handle is perpendicular in position to the hook to ensurethat the downward stress on the shaft from the lifting of the heavyweight placed on the hook during lifting is evenly distributed on eitherside of the handle.

[0064] While some embodiments of the present invention have beendescribed in the foregoing, it is to be understood that otherembodiments are possible within the scope of the invention. Theinvention is to be considered limited solely by the scope of theappended Claims.

1. A lifting device comprising: an elongate shaft member extending in alongitudinal direction between respective first and second ends; a hookmember supported on the first end of the shaft member, the hook memberbeing substantially straight along a hook axis lying substantiallyperpendicular to the longitudinal direction of the shaft member; and agripping member supported on the shaft member adjacent the second endthereof for being gripped in a hand of a person.
 2. The device accordingto claim 1 wherein the shaft member and the hook member are integrallyformed of a single rod of material which has been deformed.
 3. Thedevice according to claim 1 wherein the shaft member is circular incross section at the first end thereof.
 4. The device according to claim1 wherein the shaft member is approximately two feet in length.
 5. Thedevice according to claim 1 wherein the shaft member and the hook memberhave a similar cross sectional dimension which is substantially lessthan ½ inch.
 6. The device according to claim 1 wherein the grippingmember comprises a handle mounted on the shaft member transversely tothe longitudinal direction of the shaft member and the hook axis.
 7. Thedevice according to claim 6 wherein the handle is fixed in orientationrelative to the shaft member and the hook member.
 8. The deviceaccording to claim 6 wherein the handle is injection molded about thesecond end of the shaft member.
 9. The device according to claim 8wherein the second end of the shaft member is deformed before the handleis injection molded thereabout.
 10. A lifting kit for lifting objectshaving a flat bottom supported on particulate material and the like, thekit comprising a plurality of lifting devices in accordance withclaim
 1. 11. A method of lifting an object having a flat bottomsupported on particulate material on the ground, the method comprising:providing at least one lifting device comprising an elongate shaftmember; a hook member supported on a first end of the shaft member toextend substantially straight along a hook axis lying substantiallyperpendicular to a longitudinal direction of the shaft member; and agripping member supported on the shaft member adjacent a second endthereof; positioning the hook member of said at least one lifting deviceadjacent and parallel to a respective side edge of the object; loweringthe hook member of said at least one lifting device along the respectiveside edge below a respective bottom edge of the object; rotating thehook member of said at least one lifting device about a longitudinalaxis of the shaft member until the hook member is positioned below theobject; and lifting said at least one lifting device.
 12. The methodaccording to claim 11 including providing a plurality of lifting devicesand positioning the lifting devices along opposing side edges of theobject.
 13. The method according to claim 11 for an object comprising afirst pre-cast concrete sidewalk slab positioned adjacent a secondsidewalk slab of similar configuration, the method including insertingthe hook member of said at least one lifting device in a gap definedbetween the first and second sidewalk slabs.